1. Field of the Invention
The present invention relates to the reinforcing of natural or synthetic elastomers by means of a particular silica composition.
2. Description of the Prior Art
A very large number of formulations exist in this art of rubber mixtures in which an elastomer constitutes the principal component, having regard for the multiplicity of uses for which such mixtures are intended: tires, shoe soles, cables, joints, seals, etc.
Other than the elastomer, such formulations typically include fillers, one of the main functions of which is to improve the mechanical properties of the elastomer. Among such fillers, carbon blacks are particularly widely used.
However, for a number of years attempts have been ongoing to replace carbon blacks with precipitated silicas, which are far more economical.
Nonetheless, replacing carbon blacks by silicas is not a simple matter. Indeed, reinforcing fillers owe certain of their properties to the morphology of their aggregates. As such morphology is different as between the silicas and carbon blacks, it will be appreciated that substantial differences may occur in regard to elastomers which are reinforced by one or another of such types of fillers.
Therefore, the present inventors have now carried out long-term studies to determine those types of silicas which are most suitable for reinforcing elastomers and, in particular, those which have reinforcing properties which are most akin to the reinforcing properties of carbon blacks.
As a result, a correlation has now been found between the morphological properties of silicas and the properties of elastomers reinforced with such fillers.